build(web): node-server preset (apt-native runtime, no bun dependency)

Switch the Nitro build preset from `bun` to `node-server` so the built
.output/server is a standalone HTTP server runnable by apt-native `node`
(validated: `node .output/server/index.mjs` → Listening, /login 200 on node
v25.9.0). This lets the upcoming punktfunk-web .deb depend on `nodejs (>= 20)`
instead of vendoring the bun binary. CI still BUILDS with bun; only the runtime
target changes, and bun still runs a node-server build, so existing
`bun run .output/server/index.mjs` deployments keep working. `vite dev` is
unaffected. Prereq for bundling the web console into the apt install.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/vite.config.ts

@@ -41,7 +41,11 @@ export default defineConfig({
     // proxies to the management host injecting the bearer token server-side) — NOT a static
     // routeRule, so the proxy runs behind the login gate and reads env at runtime.
     nitroV2Plugin({
-      preset: 'bun',
+      // node-server (not bun): a STANDALONE node HTTP server (`node .output/server/index.mjs`
+      // listens — the plain `node` preset only exports a handler). Lets the bundled punktfunk-web
+      // .deb depend on apt-native `nodejs (>= 20)` instead of vendoring bun. CI still BUILDS with
+      // bun; only the runtime target changes. (dev `vite dev` is unaffected.)
+      preset: 'node-server',
       compatibilityDate: '2026-06-10',
       // Scan server/{middleware,routes} for the auth gate + the /api proxy.
       scanDirs: [serverDir],